package thebeast.util;
/*

   Porter stemmer in Java. The original paper is in

       Porter, 1980, An algorithm for suffix stripping, Program, Vol. 14,
       no. 3, pp 130-137,

   See also http://www.tartarus.org/~martin/PorterStemmer

   History:

   Release 1

   Bug 1 (reported by Gonzalo Parra 16/10/99) fixed as marked below.
   The words 'aed', 'eed', 'oed' leave k at 'a' for step 3, and b[k-1]
   is then out outside the bounds of b.

   Release 2

   Similarly,

   Bug 2 (reported by Steve Dyrdahl 22/2/00) fixed as marked below.
   'ion' by itself leaves j = -1 in the test for 'ion' in step 5, and
   b[j] is then outside the bounds of b.

   Release 3

   Considerably revised 4/9/00 in the light of many helpful suggestions
   from Brian Goetz of Quiotix Corporation (brian@quiotix.com).

   Release 4

*/

import java.io.*;

/**
 * Stemmer, implementing the Porter Stemming Algorithm
 * <p/>
 * The Stemmer class transforms a word into its root form.  The input
 * word can be provided a character at time (by calling add()), or at once
 * by calling one of the various stem(something) methods.
 */

class Stemmer {
  private char[] b;
  private int i,     /* offset into b */
          i_end, /* offset to end of stemmed word */
          j, k;
  private static final int INC = 50;

  /* unit of size whereby b is increased */
  public Stemmer() {
    b = new char[INC];
    i = 0;
    i_end = 0;
  }

  /**
   * Add a character to the word being stemmed.  When you are finished
   * adding characters, you can call stem(void) to stem the word.
   */

  public void add(char ch) {
    if (i == b.length) {
      char[] new_b = new char[i + INC];
      for (int c = 0; c < i; c++) new_b[c] = b[c];
      b = new_b;
    }
    b[i++] = ch;
  }


  /**
   * Adds wLen characters to the word being stemmed contained in a portion
   * of a char[] array. This is like repeated calls of add(char ch), but
   * faster.
   */

  public void add(char[] w, int wLen) {
    if (i + wLen >= b.length) {
      char[] new_b = new char[i + wLen + INC];
      for (int c = 0; c < i; c++) new_b[c] = b[c];
      b = new_b;
    }
    for (int c = 0; c < wLen; c++) b[i++] = w[c];
  }

  /**
   * After a word has been stemmed, it can be retrieved by toString(),
   * or a reference to the internal buffer can be retrieved by getResultBuffer
   * and getResultLength (which is generally more efficient.)
   */
  public String toString() {
    return new String(b, 0, i_end);
  }

  /**
   * Returns the length of the word resulting from the stemming process.
   */
  public int getResultLength() {
    return i_end;
  }

  /**
   * Returns a reference to a character buffer containing the results of
   * the stemming process.  You also need to consult getResultLength()
   * to determine the length of the result.
   */
  public char[] getResultBuffer() {
    return b;
  }

  /* cons(i) is true <=> b[i] is a consonant. */

  private final boolean cons(int i) {
    switch (b[i]) {
      case'a':
      case'e':
      case'i':
      case'o':
      case'u':
        return false;
      case'y':
        return (i == 0) ? true : !cons(i - 1);
      default:
        return true;
    }
  }

  /* m() measures the number of consonant sequences between 0 and j. if c is
     a consonant sequence and v a vowel sequence, and <..> indicates arbitrary
     presence,

        <c><v>       gives 0
        <c>vc<v>     gives 1
        <c>vcvc<v>   gives 2
        <c>vcvcvc<v> gives 3
        ....
  */

  private final int m() {
    int n = 0;
    int i = 0;
    while (true) {
      if (i > j) return n;
      if (!cons(i)) break;
      i++;
    }
    i++;
    while (true) {
      while (true) {
        if (i > j) return n;
        if (cons(i)) break;
        i++;
      }
      i++;
      n++;
      while (true) {
        if (i > j) return n;
        if (!cons(i)) break;
        i++;
      }
      i++;
    }
  }

  /* vowelinstem() is true <=> 0,...j contains a vowel */

  private final boolean vowelinstem() {
    int i;
    for (i = 0; i <= j; i++) if (!cons(i)) return true;
    return false;
  }

  /* doublec(j) is true <=> j,(j-1) contain a double consonant. */

  private final boolean doublec(int j) {
    if (j < 1) return false;
    if (b[j] != b[j - 1]) return false;
    return cons(j);
  }

  /* cvc(i) is true <=> i-2,i-1,i has the form consonant - vowel - consonant
     and also if the second c is not w,x or y. this is used when trying to
     restore an e at the end of a short word. e.g.

        cav(e), lov(e), hop(e), crim(e), but
        snow, box, tray.

  */

  private final boolean cvc(int i) {
    if (i < 2 || !cons(i) || cons(i - 1) || !cons(i - 2)) return false;
    {
      int ch = b[i];
      if (ch == 'w' || ch == 'x' || ch == 'y') return false;
    }
    return true;
  }

  private final boolean ends(String s) {
    int l = s.length();
    int o = k - l + 1;
    if (o < 0) return false;
    for (int i = 0; i < l; i++) if (b[o + i] != s.charAt(i)) return false;
    j = k - l;
    return true;
  }

  /* setto(s) sets (j+1),...k to the characters in the string s, readjusting
 k. */

  private final void setto(String s) {
    int l = s.length();
    int o = j + 1;
    for (int i = 0; i < l; i++) b[o + i] = s.charAt(i);
    k = j + l;
  }

  /* r(s) is used further down. */

  private final void r(String s) {
    if (m() > 0) setto(s);
  }

  /* step1() gets rid of plurals and -ed or -ing. e.g.

         caresses  ->  caress
         ponies    ->  poni
         ties      ->  ti
         caress    ->  caress
         cats      ->  cat

         feed      ->  feed
         agreed    ->  agree
         disabled  ->  disable

         matting   ->  mat
         mating    ->  mate
         meeting   ->  meet
         milling   ->  mill
         messing   ->  mess

         meetings  ->  meet

  */

  private final void step1() {
    if (b[k] == 's') {
      if (ends("sses")) k -= 2;
      else if (ends("ies")) setto("i");
      else if (b[k - 1] != 's') k--;
    }
    if (ends("eed")) {
      if (m() > 0) k--;
    } else if ((ends("ed") || ends("ing")) && vowelinstem()) {
      k = j;
      if (ends("at")) setto("ate");
      else if (ends("bl")) setto("ble");
      else if (ends("iz")) setto("ize");
      else if (doublec(k)) {
        k--;
        {
          int ch = b[k];
          if (ch == 'l' || ch == 's' || ch == 'z') k++;
        }
      } else if (m() == 1 && cvc(k)) setto("e");
    }
  }

  /* step2() turns terminal y to i when there is another vowel in the stem. */

  private final void step2() {
    if (ends("y") && vowelinstem()) b[k] = 'i';
  }

  /* step3() maps double suffices to single ones. so -ization ( = -ize plus
-ation) maps to -ize etc. note that the string before the suffix must give
m() > 0. */

  private final void step3() {
    if (k == 0) return; /* For Bug 1 */
    switch (b[k - 1]) {
      case'a':
        if (ends("ational")) {
          r("ate");
          break;
        }
        if (ends("tional")) {
          r("tion");
          break;
        }
        break;
      case'c':
        if (ends("enci")) {
          r("ence");
          break;
        }
        if (ends("anci")) {
          r("ance");
          break;
        }
        break;
      case'e':
        if (ends("izer")) {
          r("ize");
          break;
        }
        break;
      case'l':
        if (ends("bli")) {
          r("ble");
          break;
        }
        if (ends("alli")) {
          r("al");
          break;
        }
        if (ends("entli")) {
          r("ent");
          break;
        }
        if (ends("eli")) {
          r("e");
          break;
        }
        if (ends("ousli")) {
          r("ous");
          break;
        }
        break;
      case'o':
        if (ends("ization")) {
          r("ize");
          break;
        }
        if (ends("ation")) {
          r("ate");
          break;
        }
        if (ends("ator")) {
          r("ate");
          break;
        }
        break;
      case's':
        if (ends("alism")) {
          r("al");
          break;
        }
        if (ends("iveness")) {
          r("ive");
          break;
        }
        if (ends("fulness")) {
          r("ful");
          break;
        }
        if (ends("ousness")) {
          r("ous");
          break;
        }
        break;
      case't':
        if (ends("aliti")) {
          r("al");
          break;
        }
        if (ends("iviti")) {
          r("ive");
          break;
        }
        if (ends("biliti")) {
          r("ble");
          break;
        }
        break;
      case'g':
        if (ends("logi")) {
          r("log");
          break;
        }
    }
  }

  /* step4() deals with -ic-, -full, -ness etc. similar strategy to step3. */

  private final void step4() {
    switch (b[k]) {
      case'e':
        if (ends("icate")) {
          r("ic");
          break;
        }
        if (ends("ative")) {
          r("");
          break;
        }
        if (ends("alize")) {
          r("al");
          break;
        }
        break;
      case'i':
        if (ends("iciti")) {
          r("ic");
          break;
        }
        break;
      case'l':
        if (ends("ical")) {
          r("ic");
          break;
        }
        if (ends("ful")) {
          r("");
          break;
        }
        break;
      case's':
        if (ends("ness")) {
          r("");
          break;
        }
        break;
    }
  }

  /* step5() takes off -ant, -ence etc., in context <c>vcvc<v>. */

  private final void step5() {
    if (k == 0) return; /* for Bug 1 */
    switch (b[k - 1]) {
      case'a':
        if (ends("al")) break;
        return;
      case'c':
        if (ends("ance")) break;
        if (ends("ence")) break;
        return;
      case'e':
        if (ends("er")) break;
        return;
      case'i':
        if (ends("ic")) break;
        return;
      case'l':
        if (ends("able")) break;
        if (ends("ible")) break;
        return;
      case'n':
        if (ends("ant")) break;
        if (ends("ement")) break;
        if (ends("ment")) break;
        /* element etc. not stripped before the m */
        if (ends("ent")) break;
        return;
      case'o':
        if (ends("ion") && j >= 0 && (b[j] == 's' || b[j] == 't')) break;
        /* j >= 0 fixes Bug 2 */
        if (ends("ou")) break;
        return;
        /* takes care of -ous */
      case's':
        if (ends("ism")) break;
        return;
      case't':
        if (ends("ate")) break;
        if (ends("iti")) break;
        return;
      case'u':
        if (ends("ous")) break;
        return;
      case'v':
        if (ends("ive")) break;
        return;
      case'z':
        if (ends("ize")) break;
        return;
      default:
        return;
    }
    if (m() > 1) k = j;
  }

  /* step6() removes a final -e if m() > 1. */

  private final void step6() {
    j = k;
    if (b[k] == 'e') {
      int a = m();
      if (a > 1 || a == 1 && !cvc(k - 1)) k--;
    }
    if (b[k] == 'l' && doublec(k) && m() > 1) k--;
  }

  /**
   * Stem the word placed into the Stemmer buffer through calls to add().
   * Returns true if the stemming process resulted in a word different
   * from the input.  You can retrieve the result with
   * getResultLength()/getResultBuffer() or toString().
   */
  public void stem() {
    k = i - 1;
    if (k > 1) {
      step1();
      step2();
      step3();
      step4();
      step5();
      step6();
    }
    i_end = k + 1;
    i = 0;
  }

  /**
   * Test program for demonstrating the Stemmer.  It reads text from a
   * a list of files, stems each word, and writes the result to standard
   * output. Note that the word stemmed is expected to be in lower case:
   * forcing lower case must be done outside the Stemmer class.
   * Usage: Stemmer file-name file-name ...
   */
  public static void main(String[] args) {
    char[] w = new char[501];
    Stemmer s = new Stemmer();
    for (int i = 0; i < args.length; i++)
      try {
        FileInputStream in = new FileInputStream(args[i]);

        try {
          while (true)

          {
            int ch = in.read();
            if (Character.isLetter((char) ch)) {
              int j = 0;
              while (true) {
                ch = Character.toLowerCase((char) ch);
                w[j] = (char) ch;
                if (j < 500) j++;
                ch = in.read();
                if (!Character.isLetter((char) ch)) {
                  /* to test add(char ch) */
                  for (int c = 0; c < j; c++) s.add(w[c]);

                  /* or, to test add(char[] w, int j) */
                  /* s.add(w, j); */

                  s.stem();
                  {
                    String u;

                    /* and now, to test toString() : */
                    u = s.toString();

                    /* to test getResultBuffer(), getResultLength() : */
                    /* u = new String(s.getResultBuffer(), 0, s.getResultLength()); */

                    System.out.print(u);
                  }
                  break;
                }
              }
            }
            if (ch < 0) break;
            System.out.print((char) ch);
          }
        }
        catch (IOException e) {
          System.out.println("error reading " + args[i]);
          break;
        }
      }
      catch (FileNotFoundException e) {
        System.out.println("file " + args[i] + " not found");
        break;
      }
  }
}
